Method of making dies



Dec. 2, 1952 5 LANGE 2,619,853

METHOD OF MAKING DIES Filed Sept. 25, 1947 'I r 4% 5 3. 11 A 4 IN V EN TOR.

I M am Patented Dec. 2, 1952 METHOD or MAKING DIES' Sven Ragnar 'Lange, Stockholm, Sweden, assignor to .Aktiebolaget Elektrolux, Stockholm, Sweden, rc pp iion w d n Application September 23, 1947, SerialNo, 7 75,662

In Sweden October 17; 1946' 8 Cla msw nvention relates td ametnod: for. making diesr pnmachine .tOQls;

In making.- diesrit hasusually been thepractice tqiorm; an opening. or aperture therein by ma,-v chinin-g; milling, grinding; and filing opera-tipns, for example. 'Makingdies in thismanner havingenings or apertures of precise dimension and Shape. is: not. only tedious and time-consuming, butisscostlyand usually: requires the services of attisianswho are especiallyskilled'in die-making.

Animportan-t object ofrthe invention is-to providezanimproved method of making, dies of this type which overcomes the disadvantages of exist-1 ingpracticesv and .is simple and inexpensive.

Another object of the. invention is to provide such. an improved method for making dies in which a punch or punches with which a. die: is. ultimately-used may be advantageously employed to manufacture the die.

A. further object. of the invention is to employ in such: improved method an auxiliary die for making a final die; adapted for use with the punch of'a machine toolifor stampingwork pieces.

A sti-lli'further object of the invention is to employ in such improved method an auxiliary die for-medof a plurality of plates which are joined together. to form a unitary body, the individual plates: having: openings or apertures formed therein which aresubstantially'in alignment.

While the method of the invention can be practiced advantageouslyto manufacture dies having openings: or apertures of any desired shape, the method lendsitselt to the making of dies having apertureswhich are of" non-circular shape for stampingirregularand intricate shaped apertures ornotches in work pieces. Moreover, the method of the invention can be employed for simultaneously manufacturing a number of dies with precision, wherebyseveral dies which are exact duplicates can be made with very little deviation in dimensions from one another.

My. invention will be better understood" from therfollowing: descriptionwhen taken into connection-with the. accompanying drawing, and its scope will be. pointed out withparticularity in the appended claims.

In'the accompanying drawing Fig. '1 diagrammatically illustrates an initial step in manufacturing a die, in accordance with the invention; Fig. 2. diagrammatically illustrates an intermediate/Step. in; manufacturing the die; Fig. 3 diarammati a ly l ustra e an advanc s p in manufacturing the die Fig. 4 isa sectional view, taken; at line-.414 of Fig.. 5, of. a die made in accordance with. the invention; Fig. dis. a topv plan.

2 2 ew rthe;d asbqwnp na' s-. 5; l a ;1 5 9:- o i w Q a auxiliar d cfqrmedr nan n er-=- med te ter-0 3;. he me hod and t a d. hich. he ie shown n Fi s and: 5 s. mans: a fiure id-ran d tem an -R sa ials all llus ates; a: st 0i ha p eniiqn. se entto hatashq nj cE e-BK Ac o din herresent prention; a. P141 9110? a ma h cs aql smade ui cu t mar m r: w o m. a o nin qrn ic 3 a e nitesra e in Q k-;p ec s-. s n; tampinsrre a or. x: mple n i ar -l stm e a. n mbe 1 punches Ill-formed to stamp openings; in work: pieces which areof the-shape shown in Fig. 5; e p c es 1 a e mounted n a, p h. l er-- l I arrane u table manner n a hu 12 adapted t be installed for vertical. e i r c t ry movement in a stamping press.

In making-adie in accord with the invention the punches Ill are employed to stamp a pad: It, to form what maybe referred to as-a first auxil: iary die. The pad [3; is preferably formed1o fmaterial-Which is hard; and relatively; tough and: in which sharply defined: impressions can be stampedby the punches. "I. By way of example;

I have found a, pad l3: formed ofa resinous phenoliccondensation product, such as that com-... mercially known as Bakelite, very satisfactory.

The pad: l3.:mayconsistpfisuitable. fabric impregmated with suchv agresinousproduct. It is to be understood that other materials possessing physical properties generally similar to. Bakelite, as regards toughness and. durability, may be used. In stamping. the pad: lt the latter is placed in a chuckof the. stamping press, and the punches III. are forced downwardlyinto the pad to form re-v cesses [4; as shown in Fig. l. The recesses Mare. well defined and have sharp edges and conform, to the cross-sectional. shapes of the punches Hi.

The punches are moved upwardly and a metallic plate [5 is thenplaced over the stamp pad l3, as shown in Fig. 2'. Thepunches [0 are then forced downwardly. again to stamp openings in the plate. [5 with the stamped pad l3 serving as a first auxiliary die. Theplate l5 is preferably formed. of relatively hard metal sheeting, such as hardened: strip steel or like material, forexample; and such plate, together with a number of similarly stamped plates, are bundled into a package to form a second auxiliary die in accord with the invention.

In order'to facilitate. the. making ofthe. second auxiliary die. according: to one embodiment ofthe invention, the pad: [3; is. removed from thestampe ins press. and: replaced by a hardened steel back:

ing plate which has been plane ground. The stamped plate I5 is placed on the backing plate on top of which in turn is positioned a plate formed of relatively soft material, such as brass or aluminum, for example. The punches III are then forced downwardly to stamp the plate of soft material while the stamped plate I5 serves as an auxiliary die. The plate of soft material is then removed while the material stamped therefrom and forced into the bottom parts of the openings in the stamped plate I5 is allowed to remain therein. 7

A second plate I5 like the first stamped plate I 5 is then placed over the latter, and the punches I I! forced downwardly to stamp such second plate while the first stamped plate I5 serves as an auxiliary die. The material stamped from the second plate I5 by the punches II! is pushed downwardly such a distance that the lower parts thereof are disposed within the openings in the first stamped plate I5 and the upper parts thereof are disposed within the stamped-out portions of the second plate I5. In this way the stamped-out material, which may be referred to as cuttings or leavings, are effectively used as a joint and guide between the first and second stamped plates I5.

A third plate I5 is placed over the second plate I5 and stamped by the punches ID, the material stamped from such third plate being forced downwardly such a distance into the stampedout portions of the second plate that it effectively joins and holds together the second and third plates; Additional plates I5 are successively placed on the package of plates being built up and stamped in the manner just described until a bundle of desired thickness is obtained. In this way the material punched out of each plate I5 is partially moved into the opening of the next lower plate. While building up the bundle of plates I5 the stamped material is allowed to remain in the cut-out portions to hold the plates together. Before the cuttings or leavings are removed, the plates I5 are joined together in any suitable manner, as by welding or riveting, for example, to form a unitary body II which may be referred to as the second auxiliary die. As shown in Fig. 6, the plates I5 are securely fastened together by countersunk rivets I6, and the leavings 'or cuttings then removed from the stamped-out portions of the plates.

The final die is formed from a block or plate I8 offerrous metal which is relatively soft and capable of being hardened. In making the die from'the plate I8, the latter is placed on the second auxiliary die II, which, in turn, is fixed to and rests on a surface ground hardened base member I9. After the plate I8 and second auxiliary die II are oriented and secured in position, the punches ID are forced downwardly to stamp the openings in the plate I8, as shown in Fig. 3.

The plate I8 is surface ground and the openings formed therein are cleaned, that is, reamed or drifted, so as to provide suitable clearance or play between the punches and the openings in the die I8. I accomplish this by upsetting the ends of each punch I0 to form a flange which serves as a trimming edge or drift ledge, as indicated at 20 in Fig. 7. The punches III are then mounted in the stamping press and forced downwardly through the openings in the die I8, whereby the die openings are effectively cleaned to provide the desired clearance between each punch andthe die opening through which it passes.

In order to make the punches I0 and die I8 ready for use to operate on work pieces, the up- '4 set ends or flanges of the punches are removed in any suitable manner, as by grinding, for example. The final die or pad I8 is carbonized or charged with carbon and hardened in any well known manner. After being hardened, the die I8 is desirably tempered and then ground smooth.

In order to illustrate better the method of making dies in accordance with the invention, the following example of one application of the method is given for the purpose of illustration only. A pad I3 was employed formed of fabric impregnatedwith Bakelite, and the punches III forced downwardly therein for a distance of about 1 mm. to form the recesses I4. A plate I5 formed of hardened strip steel, having a thickness of about 1.1 mm., was then positioned over the pad I3 and stamped by the punches to form openings therein. The pad I3 was then replaced by a surface ground hardened steel plate over which the stamped plate I5 was positioned. A brass plate having a thickness of about 0.5 mm. was placed over the stamped plate I5, and the punches II! moved downwardly to force the stamped brass material into the lower part of the openings in the plate I5.

A bundle of hardened steel plates I5,each having a thickness of about 1.1 mm., was then built I plate I8 of soft iron positioned over the plate bundle H, such plate I8 having a thickness of about 5.5 mm. The plate I8 was stamped in the manner previously described after which the openings formed therein were cleaned out by upsetting the ends of the punches I0. Thereafter, the upset ends of the punches were ground smooth and the plate I8 case-hardened, temperedand ground smooth to make it ready for operating on work pieces.

It will now be seen that I have provided an improved method f making dies in which the punch or punches with which the die is intended to be used are advantageously employed to manufacture the die. The method of the invention lends itself to making several dies at the same time from a single block or plate'which can thereafter be subdivided to provide the individual dies. When several punches are employed, as in the embodiment described, it may sometimes be desirable initially to operate only'a few punches in the different stamping operations,

and progressively increase the number of punches used so as to reduce the pressure required of the machine tool in the stamping operations.

The plate bundle or second auxiliary die I! desirably is formed of plates each having a thickness which is'less than that of the plate from which the final die is produced. The overall thickness of the plate bundle I'I preferably is approximately'equal to or possibly greater than the plate or block I8. By forming the plate bundle of sheets of hard strip steel or like material, a second auxiliary die is provided which is extremely effective for producing the final die.

'Iirorderi to facilitate making; the: pad; [13, the punches: I maybe-initially brought: against. the pad so; as. to: mark. an: outline. thereon: of" the: stamping which. is; ultimately: made by each punchs. A region of? the. pad l3? within" each marked outlines. produced: may" be drilled to: a depth of: about 3t mm. by a. drill or milling: tool offsuchlsizelthat the f drilledtopening. is well within the outline? marked. by each punclr. When: each punch isisub's'equently actuated to: form a. recess t4: initheidrilled pad; lesspressure' i's requiredin. the stamping operation, and the tendency for the material to creep issub'st'antially reduced so that recesses having extremely sharp edges will be produced.

Itistobe-understoodthat themethod described herein is susceptible of modifications. and. changes without departing from. the. spirit, and scope of the invention. Thus, in certain instances it may be preferable to use the pad 13 as an auxiliary die for stamping all of the plates l which are to--be .joinedtogether to form the plate bundle orsecond auxiliary die II. It is also possible to makethe" punchor punches from a finished or completed die. Therefore, I do not wish to be limited to* the particular embodiment described, and Iiintend in the following claims to cover all modificationswhichdo-not depart from the spirit and scope of my invention.

What is claimedis:

' IVA method ofmaking afinal' die foruse with a punch of a machine tool, which includes forming a. first auxiliary die by stamping with the punch a pad comprisingaphenolic'condensation product or like material possessing generally similar physical properties as: regards toughness and workability; forming a second auxiliary die by a process which includes the step of stamping an element with the punch while such element is backed up by the first auxiliary die, and stamping a part with the punch while such part is backed up by the second auxiliary die to form the final die adapted for use with the punch for operating on work pieces.

2. The method set forth in claim 1 in which said pad comprises fabric impregnated with said phenolic condensation product or like material possessing generally similar physical properties as regards toughness and workability.

3. The method set forth in claim 1 in which the second auxiliary die comprises a number of relatively hard metallic plates of which said element constitutes one such plate, each plate having a thickness less than that of said part, the second auxiliary die being formed by a process which further includes the steps of stamping openings in the plates with the punch, and uniting the plates to form a unitary body constituting the second auxiliary die in which the openings formed by the punch are substantially in alignment.

4. The method set forth in claim 3 in which the final die comprises a metallic body, the plates when united forming said unitary body having an overall thickness which is substantially at least as great as the thickness of said metallic body.

5. In the method set forth in claim 1 in which the second auxiliary die comprises a number of relatively hard metallic plates of which said element constitutes one such plate, each plate having a thickness less than that of said part, the second auxiliary die being formed by a process which further includes the steps of stamping openings in all of said plates with the punch-and uniting the plates to form a unitary body constituting the second auxiliary die in which the 63 openings. formediby the punch. aresubstantially in alignment.

- 6 In..the:method set forthin: claim; 11 in. which the second auxiliary die comprises a number'of relatively hard metallic: plates ofrwhichsaid. element: constitutes one: such. plate; each: platehavinga. thickness? less. than that: of said part, the secondi'auxiliary'diebeing formed by a process which further. includes thesteps. of: stamping anopening in-said. plates while successively employingas an auxiliary die memberthe. plate previously having an opening stampedtherein, and

unitingthe plates to form. a unitary body: constituting:thesecondauxiliarydiein which. theeopenings. formed-f by the. punch are substantially in: alignment:

7..In theimethod set forthv in claim-.61 which.

includes the .step. of placing? said; one stamped plate on;a hard base-member while serving; as an auxiliary die for stamping anopening in anotheror'se'condplate; with the punch.

81. In. the method. setiforthinv claim '7 which includes the steps :.of-stamping'theopening inthe:

second: plate so that the material punched therefrom partially moves into'the opening in said one plate to. hold the first andsecondxplates together as an. auxiliary die member while stamping a third plate, and stamping the opening in the third;

plate so that. the. material punched: therefrom partially moves: into the opening in. the second plateztoi hold thesecond andthird plates together.

9: In the method set. forth in claim 8 which includes the steps; of stamping'an' opening with the punch in. a relatively soft metallic sheet formed of brass" or-aluminum or like material, for

example, While employing said one or first stamped'plate asan: auxiliary die member so that the material punched'therefrom moves into the opening in said one plate, said metallic sheetbeing of less thickness than the first stamped plate, removing said sheet while leaving the punched material therefrom in the opening in said first plate, and then utilizing said first plate as an auxiliary die member for stamping an opening in the second plate with the punch.

10. In the method set forth in claim 1 in which the second auxiliary die comprises a number of relatively hard metallic plates of which said element constitutes one such plate, each plate having a thickness less than that of said part, the second auxiliary die being formed by a process. which further includes the steps of stamping an opening in said plates while successively employing as an auxiliary die member the plate previously having an opening stamped therein, keeping each plate on top of the previously stamped plate so that the material punched therefrom partially moves into the opening in the next lower plate to hold the plates together by the material punched out of the openings formed in the plates, uniting the plates to form a unitary body constituting the second auxiliary die in which the openings formed by the punch are substantially in align ment, and then removing the punched material from the openings before utilizing the second auxiliary die to form the final die.

11. In the method set forth in claim 1 in which said part comprises a body of ferrous metal which is relatively soft, the further step of hardening said body after being stamped with the punch.

12. In the method set forth in claim 11 which includes the step of reaming or drifting the opening in said part before the latter is hardened with the aid of a punch which is flanged to provide a reaming or drift ledge.

7 13 In'the method set forth in claim 12 which includes the step of grinding the punch to remove the drift ledge when reaming or drifting is completed.

14. In the method set forth in claim 1 in which said part comprises a body of relatively soft ferrous metal, the steps which include upsetting the punch to form a drift ledge, reaming or drifting the opening in said part to clean out the latter, grinding the upset punch to remove the drift ledge, and hardening said part when the opening therein is cleaned.

15. In the method set forth in claim 1 which includes the steps of initially bringing the punch against said pad so as to mark an outline thereon of the stamping to be effected by the punch, and drilling said pad within the marked outline to facilitate the stamping of said pad.

16. A method of making a final die for use with a plurality of punches associated with a machine tool, which includes forming a first auxiliary die by stamping with the punches a pad comprising a phenolic condensation product or like material possessing generally similar physical properties as regards toughness and workability, forming a second auxiliary die by a process which includes the step of stamping an element with the punches while such element is backed up by the first auxiliary die, and stamping a part with the punches while such part is backed up by the second auxiliary die to form the final die adapted for use with the punches for operating on work pieces.

17. In the method set forth in claim 16 which includes the steps of successively increasing the number of punches employed on the machine tool 3 when stamping said pad so as to reduce the pressure required of the machine tool to effect said stamping and also counteract creeping of the material.

18. In the method set forth in claim 16in which the second auxiliary die comprises a number of plates formed of steel or like material of which said element constitutes one such plate, each plate having a thickness less than that of said part, the second auxiliary die being formed by a process which further includes the steps of stamping openings in the plates with the punches, and uniting the plates to form a unitary body constituting the second auxiliary die in which the openings formed by the punches are substantially in alignment.

SVEN RAGNAR LANGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 522,953 Bradley July 10, 1894 598,867 Hartog Feb. 8, 1898 1,070,889 Hartog Aug. 19, 1913 1,571,559 Smith Feb. 2, 1926 1,662,026 Brophy Mar. 6, 1928 2,092,756 Grabec Sept. 14, 1937 2,325,989 Tryon Aug. 3, 1943 2,368,717 Marschner Feb. 6, 1945 2,400,518 Kreber et al May 21, 1946 2,494,448 Martin July 23, 1946 2,410,372 Wales Oct. 29,1946 2,413,512 Morin Dec. 31, 1946 2,440,963 Luce May 4, 1948 FOREIGN PATENTS Number Country Date 271,192 Great Britain May 26, 1927 

